Classes and Functions

[Low_Ki_]

Soooo.... So far this is what I've been able to come up with. I know it's not the most efficient but it does what I need it to for now. I know I will have to end up adding a dictionary for username:password key value pairing and checks.... JSON will probably be my best bet. But as of right now I am proud of my work so here it is. Please comment and critique :D

class Register():

    def __init__(self, prompt_message):
        self.prompt_message = prompt_message

    def user_registration(self):
        prompt_username = input(self.prompt_message)
        filename = 'guest_book.txt'
        if prompt_username.lower() != 'quit':
            with open(filename, 'a+') as file_obj:
                with open(filename, 'r') as file_obj:
                    names = file_obj.readlines()
                    for name in names:
                        if prompt_username.lower() in name.lower():
                            print("Name Taken")
                            break
                    else:
                         with open(filename, 'a') as file_obj:
                            file_obj.write(prompt_username + '\n')
                            print("Welcome to a whole new world, {}".format(prompt_username))


get_username = Register("Please enter the username you wish to create. \n\tOr type 'quit' to exit: ")
get_username.user_registration()

I use the first

with open(filename, 'a+') as file_obj:

in order to create the file incase it doesn't exist. The readlines to create a list to check for existing usernames and the next 'a' to append usernames that do not exist yet.